In a manufacturing setting, Computer Numerical Control (CNC) machines are commonly used to precisely work components. Specifically, a computer controller drives a machine tool to perform a cutting operation within a work envelope of the machine. The use of CNC machines has resulted in considerable improvements in the consistency and quality of machined parts. Further, CNC automation has reduced the time required to change the machine to produce different components.
CNC machines are generally used for drilling or tapping operations, such as an operation of drilling holes into an engine block. A typical CNC machine will have a work envelope within which the cutting operation is performed, a mounting block for holding the part to be operated upon, a spindle which generates a rotational force, a work tool for performing the drilling function, and a controller for instructing machine operation. In operation, a workpiece is placed in the mounting block, which is inside of the work envelope. The spindle, which has a drilling work tool attached, is then moved by a driver, which is directed by the controller, to drill holes in the workpiece in the correct locations along the workpiece. Generally, the spindle can be moved along the X, Y, and Z axes. A typical workpiece, such as an engine block, has six surfaces. As the workpiece must be held by the positioning block along at least one surface, the held surfaces are not available to the drilling work tool. As such, if a workpiece requires all six surfaces to be worked, the workpiece must be removed from the positioning block and reset such that the positioning block holds the workpiece along a different surface. Further, as the spindle is generally held from the top of the work envelope, the drilling is optimally carried out on the top surface of the workpiece.
In addition to improving the quality of manufactured components, improving the efficiency of the manufacturing process is also desirable. In this regard, the present CNC drilling machine has drawbacks. Placing the workpiece into the positioning block, repositioning the workpiece during operation, and removing the workpiece upon conclusion of the machining operation all reduce the efficiency of the system. Presently, the loading, unloading, and repositioning of the workpiece requires either: manpower, a separate robot, or a gantry loader.
Each of the alternatives has advantages and drawbacks. Manpower is flexible, however is also relatively expensive and can make errors in handling parts. Robots are accurate, but expensive. Gantry loaders are also expensive and must be custom designed. Further, all of the above options require the machine to be stopped and the safety doors to be opened, which in turn requires extra safety circuits and interlock programming to ensure safety.
Accordingly, a need exists in the art for an improvement in the loading, unloading, and/or repositioning of workpieces in a CNC drilling machine.